Vacuum suspension system

ABSTRACT

A vacuum suspension system includes a rigid socket defining a socket wall having exterior and interior surfaces. The socket defines an aperture extending between the exterior and interior surfaces, and has a closed distal end and an open proximal end with an interior cavity defined by the interior surface. A fluid regulator is provided at the aperture and operatively engages the fluid regulator. A pump system includes a pump and a covering for securing over the exterior surface of the socket and carrying the pump. The pump is configured for placement proximate to the fluid regulator and arranged for drawing air from the socket through the aperture. A chamber having a variable volume is formed by a space defined between the exterior surface and an inner surface of the covering proximate to the pump.

TECHNICAL FIELD

The present disclosure relates to an improved vacuum suspension systemfor securing a prosthetic socket to a user.

BACKGROUND

Amputees commonly use prosthetic devices to improve their mobility andassociated quality of life. Various types of prostheses exist forreplacing the functionality of a missing limb. Transtibial andtransfemoral prostheses are effective at helping amputees regain theability to walk on their own. Various forces cause separation between aprosthetic limb and a residual limb, especially during use. This mayhappen during the swing phase of ambulation, when a prosthetic leg issubjected to both gravitational and centrifugal forces.

The manner in which an artificial limb is attached to a residual limbdetermines the control an amputee has over the prosthesis.Traditionally, prostheses are secured to amputees' residual limbs bystraps, belts, cuffs, harnesses and/or locking pins. These devices areinconvenient and uncomfortable. They cause chafing against the patient'sbody, which leads to sores and abrasions. It is now common to use sometype of suspension system.

Amputees can secure prosthetic devices on their residual limbs by usingvarious vacuum or suction arrangements, whereby the maximum strength ofthe force holding the prosthesis to the residual limb is a function ofthe atmospheric pressure. The differential air pressure is routinelyreferred to as suction or vacuum by those having skill in the art. Tomaintain the sub-atmospheric pressure created within the distal end ofthe socket, sealing sleeves or liners have been provided to prevent aninflux of air around the distal end of the residual limb. Such linersare provided between the residual limb and the socket to provide forslight compression, and a gripping connection is provided to assist withthe suction suspension.

The liner can be rolled onto the residual limb so the liner-covered limbcan then be inserted into the prosthetic socket. The use of conventionalliners alone only provides a partial suction fit since they do not forma true air-tight seal with the socket. Some air will slowly enter thesocket, especially during the swing phase of the patient's gait andduring periods of inactivity.

Conventional vacuum systems have been used to increase the suctionwithin the socket. Such vacuum systems may utilize a valve at a distalend of an otherwise closed socket arranged to receive the distal endportion of a residual limb. These pressure-control systems work byexhausting air only from the space between the distal end of theresidual limb and the distal end of the socket interior as the limb isfully inserted into the socket. Any air that has migrated to areas otherthan the distal end can remain trapped, and this action affects theoptimal pressure differential and diminishes the strength of the suctionconnection. There is a clear need to provide a way to allow a user toexpel air from within any area of the socket.

The use of a valve is intended to allow air to be expelled from thesocket in order to maintain at least a slight negative pressure forcreating suction against the residual limb. Although the swing phase ofthe gait cycle will tend to pull the socket off the limb, walking andother weight-bearing activities may push the limb further into thesocket. Pushing the limb further into the socket causes the valve toexpel air. Conversely, directly pulling the limb out of the socket isprohibited due to the effect of suction.

Common valve systems used with prosthetic sockets have included an innerbase connected to an outer housing that can be threaded directly to thesocket wall. These types of valve systems often fail at maintaining thedesired air pressure within the socket because they are installed onflat socket wall surfaces. The inclusion of a threaded outer housinghelps to prevent air from leaking out of the socket from around thehousing instead of being expelled through the valve as intended. Withoutan air-tight seal in a vacuum suspension system, any significant loss ofsuction will cause separation of the prosthesis from the residual limb.Thus there is a clear need to provide a valve arranged in a suspensionsystem that can be adapted for effective use on a curved portion of asocket wall surface.

Other traditional sockets may include a separate, self-contained vacuumreservoir for maintaining the sub-atmospheric pressure within the socketinterior. However, the vacuum systems create additional bulk and addweight to the socket, making it more difficult for an amputee to achievenatural mobility with the attached prosthetic. Attaching such areservoir may also decrease the structural integrity of the socket sinceit may no longer conform to the residual limb and provide a smooth andcomfortable fit if it collapses.

It has been found that total contact between a residual limb and aprosthetic socket is important to attain an even weight distribution ofthe patient, which helps distribute the suspension of the prosthesisover the whole surface of the limb. As the wearer sweats, losing fluidcauses the volume of the residual limb to decrease, whichcorrespondingly alters the fit of the residual limb within the socket.Therefore, there is also a need to improve the consistency andreliability of the fit between the residual limb and the socket.

Many existing valve systems include components protruding from thesocket, making it cumbersome and uncomfortable to wear, while alsoincreasing the chance it may snag onto foreign objects. By not keeping alow profile, there is also a greater likelihood of the valve systembeing damaged. Damaging the valve would cause the air pressure withinthe socket to no longer be properly maintained, and the vacuumsuspension it provides to the residual limb would ultimately fail. Thereis a clear need for an improved pressure regulation system that is notburdensome or uncomfortable for a user, and which maintains a lowprofile.

Using a conventional valve system alone may not be an effective orefficient way to expel excess air from within the socket. Instead, it isa goal behind embodiments of the disclosure to provide a valve systemwith an improved pump to create the desired vacuum effect. Includingsuch a pump would ensure a sufficient amount of air is expelled from thesocket to create the desired suction.

Current pumps used with prosthetic sockets have disadvantages, includingtheir size, weight and difficulty of use. For many patients, thetime-consuming steps involved with operating the pump combined with thecumbersome placement and unreliability of accurately regulating pressureconvinces them to avoid using prostheses entirely. There is therefore aneed to provide an easy and quick way of adjusting the fit of theresidual limb within the socket, while making the prosthesis easier todon and doff without sacrificing comfort.

It can be seen from the foregoing there are many needs for improving onthe drawbacks of conventional vacuum suspension systems for attaching toprosthetic sockets. The embodiments of the present disclosure addressthese aforementioned shortcomings of known prosthetic systems.

SUMMARY

According to various embodiments, a vacuum suspension system is providedfor securing an amputee's residual limb to a prosthetic device. Placinga vacuum pump directly on a socket according to the present disclosureprovides a slim and effective way to ensure there is sufficient suctionsuspension to maintain a residual limb engaged with a prosthetic socket.The differential air pressure caused by using a vacuum pump createssuction that helps retain or suspend a residual limb to and within aprosthetic socket.

It should be appreciated that a liner may be worn over the residual limbso it is positioned within the hard socket to ensure the suctionsuspension created by the vacuum pump works as intended. Using a linerto provide a tight fit for the residual limb within a socket also helpsprevent air from entering the socket interior from outside of thesocket. Using vacuum pressure to maintain a reliable connection with aresidual limb improves the fit and comfort between the socket and limb.As noted, air can enter the socket interior during use if the liner doesnot form a strong air-tight seal with the socket.

It is a goal behind embodiments of the disclosure to use a vacuum pumpto expel air from a region between the socket interior and theliner-sheathed residual limb. The presence of extraneous air within thesocket decreases the suction applied to the residual limb, which maycause it to become disengaged from the socket during use. It is desiredto increase the negative pressure within this region as air is drawnout, thereby increasing the suction available to hold the prosthesis tothe residual limb. The more suction used, however, may amplify anypatient discomfort.

It is another goal of the present disclosure to provide a vacuum sourcethat a patient can control as desired to prevent possible chafing of theresidual limb. Further, it is advantageous to have a suction suspensionsystem that a patient can adjust so that wearing a prosthetic device iscomfortable. A valve system in combination with a vacuum pump is aneffective way to regulate a comfortable, yet effective level of suctionsuspension.

Yet another goal of the embodiments of the present disclosure offers afast and efficient way to operate a vacuum pump. It is advantageous toprovide an amputee with an easy and reliable way of connecting thevacuum pump on the socket. The vacuum pump of various embodiments offersa practical solution for an amputee who would otherwise need to carryaround a portable a vacuum and regularly adjust the level of suctionsuspension when needed. By attaching the vacuum pump directly to thesocket as in the embodiments, less risk of breakage can result fromrepeatedly re-attaching an external vacuum source.

The embodiments of the vacuum suspension system of the presentdisclosure provide a quick, easy and reliable way to regulate the levelof suction suspension in a prosthetic socket. By providing ahand-operated pump secured directly on the socket, a patient can adjustthe desired level of suction suspension on the fly during use or wheninitially donning the prosthesis. It should be appreciated the vacuumpump of various embodiments is relatively unobtrusive when positioned ona socket. This allows the prosthesis as a whole to keep a low profile soa user does not have to worry about constantly bumping or snagging thepump on foreign objects.

In an embodiment, a vacuum suspension system includes a rigid socketdefining a socket wall having exterior and interior surfaces. The socketdefines an aperture extending between the exterior and interior surfacesand has a closed distal end and an open proximal end with the socketforming an interior cavity defined by the interior surface. A fluidregulator, such as a one-way valve, is provided at the aperture. Thesocket is preferably sealed at the proximal end and is generallyimpermeable to air. Various means may be employed to seal the proximalend of the socket, including a sealing sleeve or rolling a portion of aliner over the brim of the socket.

A pump system includes a pump and a covering for securing over theexterior surface of the socket and carrying the pump. The pump isconfigured for placement proximate to the fluid regulator and arrangedfor drawing air from the socket through the aperture and operativelyengaging the fluid regulator. A chamber having a variable volume isformed by a space defined between the exterior surface and an innersurface of the covering proximate to the pump.

The pump system may include activation means for expanding anddecreasing the volume of the chamber. For example, the activation meansinclude a handle arranged for operating the fluid regulator and drawingair from the socket cavity. In a variation, the handle is generallyelastic and returns to a predetermined first position both prior to andat release thereof, as the handle is pulled away from the exteriorsurface of the socket.

The covering may be arranged to seal against the exterior surface of thesocket and selectively prevent escape of air from an interface formedbetween the covering and the exterior surface. In a variation, thecovering is air impermeable and seals against the exterior surface ofthe socket by compression of the covering against the socket. Thecovering may be arranged to permit escape of air from the chamber uponrelease of a handle belonging to a variation of the pump system, andforms a one-way valve with the exterior surface of the socket. Thecovering may have a channel permitting air to escape from the chamber.

The covering may be air impermeable and elastic, and may besubstantially more flexible than the exterior surface of the socket.

Various types of pumps are disclosed and arranged to operatively expandthe chamber and draw air from the socket through the fluid regulator.The covering may be adapted in a variety of configurations to permitescape of air from the chamber after or during withdrawal of air fromthe socket.

These and other features, aspects, and advantages of the presentdisclosure will become better understood regarding the followingdescription, appended claims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vacuum suspension system secured to aprosthetic socket according to an embodiment of the disclosure.

FIG. 2 is a front elevational view illustrating each individualcomponent of the on-socket vacuum pump assembly according to theembodiment of FIG. 1.

FIG. 3 is a schematic view of the prosthetic socket of FIG. 1 with avalve attached thereto.

FIG. 4 is a front elevation view of the embodiment of FIG. 1 without theliner.

FIGS. 5(a)-5(c) are cross-sectional views showing how the on-socketvacuum pump of FIG. 4 is operated.

FIG. 6 is a perspective view of the vacuum suspension system of FIG. 1having a covering with expulsion holes.

FIGS. 7(a) and 7(b) are cross-sectional views showing how the on-socketvacuum pump of FIG. 6 is operated.

FIG. 8 is a perspective view of a vacuum suspension system secured to aprosthetic socket according to another embodiment of the disclosure.

FIG. 9 is a detailed cross-sectional view of the vacuum suspensionsystem according to FIG. 8.

FIG. 10 is a front elevational view of a vacuum suspension systemsecured to prosthetic socket according to another embodiment.

FIG. 11 is a detailed cross-sectional view of an on-socket vacuum pumpaccording to another embodiment of the disclosure.

FIGS. 12(a) and 12(b) are cross-sectional views of the on-socket vacuumpump according to another embodiment of the disclosure.

FIG. 12(c) is a top plan view of the on-socket vacuum pump according toFIGS. 12(a) and 12(b).

FIG. 13 is a perspective view of the embodiment of FIG. 14 illustratinghow the on-socket vacuum pump is operated.

FIG. 14 is a detailed cross-sectional view illustrating a variation ofthe vacuum suspension system of FIG. 13.

FIG. 15 is a perspective view of another embodiment of the vacuumsuspension system of the present disclosure.

FIG. 16 is a detailed cross-sectional view of the vacuum suspensionsystem of FIG. 15 along line A-A.

The drawing figures are not drawn to scale, but instead are drawn toprovide a better understanding of the components, and are not intendedto be limiting in scope, but rather to provide exemplary illustrations.The figures illustrate exemplary embodiments of a vacuum suspensionsystem and the components, and in no way limit the structures orconfigurations of a vacuum suspension system and components according tothe present disclosure.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

A. Overview

A better understanding of different embodiments of the disclosure may behad from the following description read with the accompanying drawingsin which like reference characters refer to like elements.

While the disclosure is susceptible to various modifications andalternative constructions, certain illustrative embodiments are in thedrawings and are described below. It should be understood, however,there is no intention to limit the disclosure to the specificembodiments disclosed, but on the contrary, the intention covers allmodifications, alternative constructions, combinations, and equivalentsfalling within the spirit and scope of the disclosure.

It will be understood that, unless a term is expressly defined in thisdisclosure to possess a described meaning, there is no intent to limitthe meaning of such term, either expressly or indirectly, beyond itsplain or ordinary meaning.

The vacuum suspension system described is configured for use with aprosthetic socket, such as a lower leg prosthesis. It should beremembered, however, that the same concepts and methods described may besimilarly used for other prosthetic devices and are not limited solelyto the anatomical locations discussed.

General anatomical terms for the human body may be used for describingparticular locations of the elements of the vacuum suspension system incomparison to the human body.

The terms “proximal” and “distal” generally refer to areas on theprosthetic socket that correspond to a location relative to where aresidual limb can be inserted. For instance, the proximal end of thesocket is its open end where a residual limb is first inserted into. Thedistal end of the socket is opposite the proximal end and includes atleast part of a cavity of the socket arranged to receive a residuallimb.

B. Environment and Context of the Various Embodiments

The vacuum suspension system of the present disclosure is described foruse with a hard unitary prosthetic socket. This socket defines a shellhaving a receiving portion for a residual limb and an interior chamberfor accommodating the residual limb. The shell is preferablystructurally rigid and air impervious. It should be appreciated thatmany configurations of the socket shell may be used with the vacuumsuspension system.

Various embodiments of the vacuum suspension system may be incorporatedinto many prosthetic appliances, including above and below the kneelower limb prosthetics, and upper limb prosthetics. While the advantagesof the vacuum suspension system are discussed with respect to lower limbprostheses, similar advantages can be achieved when the vacuumsuspension system applies to upper limb prostheses.

The prosthetic socket of the present disclosure relies on vacuumpressure to ensure a secure connection with a residual limb, while alsoimproving the fit and comfort between the socket and limb. Thedifferential air pressure caused by using a vacuum pump creates asuction effect that helps retain or suspend a residual limb within aprosthetic socket.

To ensure that the suction suspension created by the vacuum pump worksas intended, a liner may be worn over the residual limb so it ispositioned within the hard socket. Besides assisting with suction insidethe socket so the residual limb does not fall out, a liner may also beworn to provide cushioning to the limb and to provide a grippingconnection to the interior surface of the socket. Using a liner toprovide a tight fit for the residual limb within a socket also helpsprevent air from entering the socket interior from outside of thesocket.

An example of a socket and method for making the same are found in U.S.Pat. No. 5,885,509, granted Mar. 23, 1999, and U.S. Pat. No. 7,105,122,granted Sep. 12, 2006, both incorporated herein by reference. Anexemplary liner sleeve for combination with the socket is found in U.S.Pat. No. 6,136,039, granted Oct. 24, 2000, U.S. Pat. No. 6,626,952,granted Sep. 30, 2003, U.S. Pat. No. 6,485,776, granted Nov. 26, 2002,U.S. Pat. No. 6,706,364, granted Mar. 16, 2004, U.S. Pat. No. 7,001,563,granted Feb. 21, 2006, and U.S. Pat. No. 7,118,602, granted Oct. 10,2006, each of which are incorporated herein by reference in theirentirety.

If the liner may not provide a true air-tight seal with the socket, someair will slowly enter the socket interior during use. The presence ofadditional air within the socket would disrupt the pressure differentialbetween the inside of the socket and the surrounding ambient air outsidethe socket, thus decreasing the suction and potentially causing the limbto become disengaged from the socket.

It is important to provide a sufficient amount of suction for suspendinga prosthesis to a residual limb during ambulation. Air may be drawn intothe interior of conventional sockets during the repeating phases of anormal gait cycle. The repetitive motions displayed between the stanceand swing phases of walking generate a pumping and pistoning effectwithin the socket, which draws in air. Even conventional prostheticsockets with sealing systems sometimes experience some air leaking intothe socket interior over a course of use.

When the pressure within the socket reaches atmospheric pressure, theincreased volume of air inside will allow the residual limb to movewithin the socket and potentially separate altogether. Any extraneousmovement of the limb within the socket could cause the patientadditional medical problems, including chafing of the skin. Moreover,patients who notice a loose connection between the residual limb and theprosthesis may also suffer increased anxiety stemming from theirinsecurity regarding whether and/or when the prosthesis will fall offtheir limb.

To combat this problem, the vacuum suspension system of the presentdisclosure can include an on-socket vacuum pump to expel air from theregion between the socket interior and the liner-sheathed residual limb.The negative pressure within this space increases as air is drawn out,correspondingly increasing the suction available to hold the prosthesisto the residual limb.

A greater amount of suction results in a more secure connection betweenthe socket and the limb. The more suction used may correlate to anincrease in patient discomfort since more chafing and/or compression maybe felt, which could further affect blood flow and circulation withinthe limb.

Including a valve system in combination with the vacuum pump can helpregulate a comfortable, yet effective pressure differential within thesocket for maintaining an appropriate level of suction suspension. Usinga valve system is also helpful in preventing a positive pressure withinthe socket interior relative to the ambient air outside the socket toallow donning the prosthesis on a limb. When used in combination withthe aforementioned vacuum pump, a valve system utilizing a check valvecan provide partial suction created naturally during ambulation. Forinstance, walking promotes weight-bearing of the limb within the socketduring the stance phase. This expels air from the socket maintaining aslight negative pressure inside the socket relative to the ambientpressure outside.

Using a vacuum pump system by itself can therefore provide a desiredamount of suction within a socket including during ambulation or whilemotionless. Alternatively, it can supplement the amount of suctionproduced by a valve during ambulation or when the socket is initiallydonned. Conventional vacuum systems, however, are bulky and oftendifficult to operate. This is because they must be connected to anexternal vacuum source provided separately from the prosthesis.

Properly connecting the vacuum pump to a prosthesis can be a verytime-consuming process, and may not be very reliable since such vacuumpumps will not work to create an adequate amount of suction within thesocket if they are not correctly attached. This makes it risky for anamputee to depend on such vacuum pumps for maintaining adequate suctionwithin a socket. This applies especially to electric pumps, which havethe tendency to break down and need repairs. It can also be impracticalfor a patient to carry around such a vacuum source over a day since itcan be rather heavy. There is a greater chance that having to frequentlyattach and detach a vacuum source can cause it to break or becomedamaged due to extended wear and tear.

Embodiments of the vacuum suspension system of the present disclosureprovide a quick, easy and reliable way to regulate the air differentialwithin a prosthetic socket for adjusting the level of suction. Byproviding a hand-operated pump secured directly on the socket, a patientcan adjust the desired level of suction suspension on the fly during useor when immobile, such as when initially donning the prosthesis. Anotheradvantage of the vacuum suspension system of the present disclosure isthat the on-socket vacuum pump is very slim, which allows the prosthesisas a whole to keep a low profile so a user does not have to worry aboutconstantly bumping or snagging the pump on foreign objects. It can beattached to most existing prosthetic sockets since it is both easy touse and to install. It should also be appreciated that placing thevacuum pump on the socket helps preserve the socket's structuralintegrity since only a small hole must be created on the socket for thepump to work as intended.

C. Embodiments of the Vacuum Suspension System

Under a first embodiment of the disclosure illustrated in FIGS. 1-4, thevacuum suspension system 20 is arranged on a hard prosthetic socket 10.An on-socket vacuum pump 24 is shown partially formed by the exteriorsurface of the socket 10 in combination with a retaining covering 22that slides over the exterior surface of the socket. It is advantageousthat the covering 22 is both elastic and removably attachable to thesocket 10 so that a patient can easily clean the socket and othercomponent parts of the prosthesis and/or pump. This also allows theindividual parts to be easily replaced or repaired if they becomedamaged.

The covering 22 is preferably fabricated from an impermeable material.Making the pump 24 detachable by sliding the covering 22 off the socket10 allows a user to remove the pump in situations that otherwise mightcause damage without compromising the suction suspension within thesocket.

A variety of suitable synthetic materials that are fluid tight,including several different plastics and/or resins, may produce thesocket 10. The socket is preferably rigid and can be formed bylamination or fabricated using various copolymers such as polyethyleneor polypropylene. Further, the socket may be fabricated based onpatient-specific anatomy and volume.

The socket 10 is donned over the patient's residual limb. A softgel-like interface liner 30 is placed on the residual limb before thelimb is inserted into the socket 10. Similar to the covering 22, thesocket liner 30 is preferably fabricated from silicone or otherimpermeable material. Because of the gel-like qualities of the liner, itmay need to be rolled onto the limb rather than directly pulled on likea sock. Rolling the liner 30 on the limb in this fashion ensures thereis only a miniscule amount of air remaining between the limb and theinner surface of the liner. The liner 30 is intended to provide a snugfit against the entire circumference of the limb. Providing a tight fithelps stop air from entering the space between the liner and the limb.This type of fit is also important to prevent the liner from beingloosened or removed from the limb when tension is applied.

The liner 30 may also provide additional cushioning to the residuallimb. The liner may create an air-tight seal for trapping air within thespace between the socket interior and the exterior of the liner. This isaccomplished by folding a proximal end 31 of the liner 30 over the outerrim 12 of the socket at its proximal end as shown in FIG. 1. Preferablythe prosthetic socket 10 is rigid so the seal formed with the liner 30is air tight. Partial suction may form between the liner-sheathed limband the socket. Maintaining such partial suction is possible if theliner is properly contoured to the shape of the residual limb. It ispreferable there are no un-sealed holes in the socket that could allowair to enter.

A total suction fit between the liner-sheathed limb and the socket,however, requires using the on-socket vacuum pump 24. A vacuum forexpelling excess air from within the socket interior may be used if thesealing engagement fails between the liner 30 and the outer rim 12 ofthe socket on which the liner is rolled over. In this situation, a slowair leak at this seal would increase the air pressure within the socket,and correspondingly cause a slow decrease for suction suspensionprovided by the socket.

The vacuum pump 24 may have the shape of a dome and may be integrallyformed on the covering 22. The covering 22 may be formed as a sleevewith open proximal and distal ends. The covering 22 is slipped over aexterior surface 13 of the socket such that the vacuum pump 24 ispositioned over a hole 14 on the socket wall as shown in FIGS. 2-4. Thehole 14 extends between the exterior surface 13 of a socket wall 11 toand interior surface 15 of the socket wall 11. The interior surface 15defines an interior cavity 17, as the socket has a closed distal end andan open proximal end.

A fluid regulator 40 is preferably situated within the hole 14 on thesocket 10 to control fluid flow between the interior and exterior of thesocket. Preferably, the fluid regulator may be a valve, and shouldregulate the air pressure within the socket so an undesirable pressuredifferential does not adversely affect donning and doffing.

The valve helps maintain a sufficient amount of suction suspension forthe prosthesis and regulates the air pressure in the socket soundesirable pressure differentials do not prevent or complicate thedonning and doffing of the socket. Valves should relieve buildup ofpressure when the liner-sheathed residual limb is inserted into thesocket. This aids in preventing a positive internal pressure relative tothe ambient air outside of the socket to allow for donning.

The valve 40 preferably may be a one-way valve, also referred to as acheck valve. A preferred type of one-way valve used with the vacuum pumpis a mushroom valve. It should be appreciated, however, that other typesof one-way valves may be described herein. The one-way valve only allowsair to be expelled from the socket for maintaining an internal negativeair pressure relative to the ambient air pressure outside the socketassisting in sustaining suction. The valve must be maintained in aclosed position so the induced sub-atmospheric pressure between thedistal end of the residual limb and distal end of the prosthetic socketresists the forces separating the socket from the limb.

The valve 40 is shown located within the wall of the socket 10 in FIG.3, but may also be located near other areas on the socket as desired ifthe valve remains in fluid communication with an interior portion of thesocket where the patient's residual limb resides. This is suitable ifnegative air pressure is formed when the residual limb is pushed deepinto the socket, expelling any remaining air. Placing the valve in theintermediate section or upper section is preferable to allow the user tomore easily reach the pump 24, and avoids potential interference with aprosthesis attached to the distal end 31 of socket.

In order to easily and quickly create sufficient suction suspension, thevacuum pump 24 can allow a user to remove any extra air left inside ofthe socket 10 that the valve 40 may fail to expel when the socket isfirst donned. Creating a stronger suction suspension than what wasinitially obtained is useful to expel additional air out from the socketbefore the user even takes a first step. By manually activating thevacuum pump 24 repeatedly to expel air from the socket interior, thevacuum suspension system 20 offers an amputee superior control over thelevel of suction suspension desired.

Using the on-socket vacuum pump 24 as discussed allows the patient todetermine the strongest suction suspension desired while still remainingcomfortable. Aligning the vacuum pump 24 directly over the valve 40allows the user to pump air out of the socket interior. This can beaccomplished by manually operating the pump by hand. The pump 24 mayinclude a handle 26 attached thereto, such that when the handle ispulled, the internal vacuum releases the valve from the socket wall anddraws air out of the socket 10. The vacuum pump 24 forces air out of thesocket 10 through the one-way valve 40 with every pull, consequentlyincreasing the negative pressure within the socket.

The section of the covering 22 integrally formed with the pump 24 ispreferably sealed against the exterior surface of the socket to maintainthe resulting vacuum pressure created from pulling the handle 26. Thissealing force is caused by the compression provided by the covering 22against the socket 10. Since the socket 10 is hard, the seal formed withthe covering 22 is air-tight.

As illustrated in FIG. 5(a), when the handle 26 is first pulled, airwithin the socket interior may evacuate from the socket interior throughthe valve 40. The air expelled from the socket interior by the pump iscollected in a chamber 50 having a variable volume defined by the spacecreated between the exterior of the socket and an inner surface 19 ofthe covering adjacent to the location where the pump is located.

Turning to FIG. 5(b), the chamber 50 expands to hold more air comingthrough the valve 40 from the socket interior as the handle 26 ispulled. Upon releasing the pump handle 26, the air collected in thechamber 50 is subsequently expelled to the atmosphere from under theperipheral ends of the covering 22. A portion of the covering 22 mayfunction as a second fluid regulator, such as a one-way valve, to letair out of the chamber 50 along the exterior surface of the socket.Manually pumping out more air from the socket not only improvessuspension, but offers better control and less pressure on the limb andliner.

FIG. 6 illustrates an embodiment of the vacuum suspension system 20having a covering 23 capable of serving as a second fluid regulator evenwhen the covering 23 substantially covers the entire socket exterior.This is accomplished by expulsion holes 28 formed within the covering 23at a location near the pump 24.

Air is drawn into the chamber 50 through valve 40 from the socketinterior when the handle is pulled away from the socket 10 as shown inFIG. 7(a). Upon release of the handle 26, the covering 23 naturallyreturns it to its original position compressing the socket 10 due to itselasticity, during which the air collected within the chamber 50 isforced out through the corresponding expulsion holes 28 as shown inFIGS. 7(a) and 7(b).

As illustrated in FIGS. 8 and 9, another embodiment of the vacuumsuspension system 120 includes a pump 124 formed by an elastic covering121 attached directly to the exterior surface of a hard prostheticsocket 110. The covering may include at least one knob 127 formedthereon, with a latch 126 provided or embedded therein. A second knob128 may be provided to help anchor the latch 126 to the covering 121,and to provide an abutment for a user to grip while pulling the latchduring operation of the pump.

The outer periphery of the covering 121 is preferably adhered to thesocket 110, and defines an air-tight chamber 150 therebetween. Thecovering 121 may be made from a flexible elastomer, such aspolyurethane, to allow expansion of the chamber 150, and may be providedfor attachment to the hard prosthetic socket 110. The covering 121 canbe configured for an air-tight sealing engagement with the socket 110 byrolling its proximal end over the brim 112 of the socket as previouslydescribed in the first embodiment. Similar to the first embodiment, thesocket 110 also includes a hole, as in FIG. 3 in the wall for receivinga fluid regulator 140, such as a one-way valve. The elastic covering 121is preferably on the socket 110 in a position over the fluid regulator140 so the chamber 150 is in fluid communication with the socketinterior via the one-way valve.

The air differential within the socket interior is maintained by theair-tight seal created between the socket 110 and the liner 130. Pullingthe latch 126 in a direction outwardly away from the socket elasticallyexpands the size of the chamber 150 and increases its volume to definean air chamber. This process creates a vacuum effect over the valve 140on the exterior surface of the socket 110. The negative pressure createdwithin the air chamber during the inflation process releases the one-wayvalve on the socket to correspondingly draw out air from within thesocket interior. The resulting increase of suction suspension helps holdthe residual limb within the socket.

A second fluid regulator, such as a one-way valve, may be on the pumpfor expelling air from the chamber out into the environment. Emptyingthe collected air from the chamber causes it to elastically return toits original non-expanded state. This allows the patient to repeatpumping additional air out from the socket interior, as desired. It isalso advantageous that the vacuum pump 124 can be attached to mostexisting prosthetic sockets and is easy to install. The hole 114 shouldfirst be drilled in the socket 110 for attaching a one-way valve 140thereto. Subsequently, the pump 124 can be adhesively bonded over thevalve to provide an air-tight seal.

It should further be appreciated that many variations of the latch 126having different shapes and sizes can be used for manipulating theelastic covering 121 to operate the pump. Although such variations maydiffer in form, they perform substantially similar functions.

FIGS. 10 and 11 illustrate an embodiment of a vacuum suspension system220 having a latch 226 connected to a single knob 227. When a user pullsthe latch 226, the knob 227 is correspondingly lifted away from theexterior surface of the socket 210, expanding the elastic covering 221.This creates a vacuum effect over a valve 240 formed in the wall of thesocket, which helps expel air out from within the socket interior.

Alternatively, FIGS. 12(a) and 12(b) show a latch 326 connected to anelastic covering 321 by a swivel member 329, such as a hinge. Theelastic covering 321 forms a sealing connection 323 with the socketexterior to define a chamber 350 having a variable volume therebetween.When the free end of the latch 326 is depressed toward the socket 310,the hinge portion is lifted and correspondingly acts to expand thechamber 350 to create a pump chamber for accumulating air, asillustrated in FIG. 12(a).

Similar to previous embodiments, the resulting pressure differentialcreated within the pump chamber draws out air from within the socketinterior through the hole 314 in the socket 310 via the fluid regulator340. When the free end of the latch is subsequently lifted away from thesocket, the pumping of air out from the socket interior ceases, asillustrated in FIG. 12(b). The accumulated air within the air chamber350 can be expelled out into the environment through an opening 327formed between the covering 321 and the socket exterior, and locatedunder the latch 326 as shown in FIG. 12(c).

By providing a vacuum pump directly on the socket, pumping can easily beaccomplished anytime during use. The pump can be operated when thesocket is initially donned, during walking when additional pushing andpulling forces apply to the residual limb, or even when sitting immobilewith no additional forces exerted on the limb. Since the pump has a lowprofile, there is less chance of it getting knocked off the socket ordamaged because of it snagging or bumping into foreign objects. Its lowprofile ensures total control of the prosthetic device is not inhibitedso that the patient can fully operate it as intended. Placing the vacuumpump directly on the socket does not make wearing the braceuncomfortable for the user. Securing the pump directly to the socketalso advantageously decreases the likelihood that a patient might losethe pump during use.

FIG. 13 shows another embodiment of the vacuum suspension systemincluding a pump system 420. An elastic covering 422 is provided forattachment to a hard prosthetic socket for receiving a fluid regulator440, such as a one-way valve. A chamber 425 having a variable volume isformed between the covering 422 and an exterior surface of the socket410 so it is correspondingly placed over the fluid regulator 440. Thechamber 425 is arranged such that it forms a substantially dome-likeshape over the fluid regulator 440.

A first connecting portion 460 may be integrally formed on the covering422 to provide fluid engagement between the chamber 425 and a tubularfluid conduit 470. The fluid conduit 470 is attached at one end to thefirst connecting portion 460, and is attached at its opposite end to asecond connecting portion 461 for providing fluid engagement to a secondpump 480. The pump 480 serves as a manual pump, such that whencompressed, the air or fluid inside is expelled through the conduit 470and into the chamber 425. This action causes the chamber 425 to inflateand form a dome-like shape protruding outwardly away from the socket 410underneath the covering 422. The chamber 425 is maintained against theexterior surface of the socket by compression supplied by the covering422.

The air differential within the socket interior is preferably maintainedby a socket liner 430 that can be rolled at its proximal end over a brimof the socket 410 to make an air-tight seal. Inflating the chamber 425creates a vacuum effect, which causes air to be drawn out through thevalve 440 from the interior of the socket 410. This air is drawn intothe air chamber 425 defined by the space created between the exterior ofthe socket and the chamber formed on the underside of the fully expandeddome-shaped chamber 450.

During use, the negative pressure created within the air chamber by thechamber 425 releases the one-way valve on the socket 410 to draw out airfrom within the socket interior. When the second pump 480 is disengaged,the air or fluid is returned to it from the chamber 425, causing thechamber to deflate. As the chamber returns to its initial pre-inflatedstate, the air drawn out from the socket interior into the chamber isexpelled into the atmosphere either through expulsion holes formed onthe covering 422 or from under the peripheral ends of the covering.

By providing the second pump 480 in fluid connection with the chamber, apumping action can be manually employed by hand or activatedautomatically during ambulation. The second pump can be placedunderneath the patient's prosthetic foot so that when pressure isnaturally applied to the second pump by the patient's weight whilewalking, the vacuum pumping process occurs.

The pump 480 may be configured to fit in an area separate from thesocket, such as in the insole of a shoe, within a foot cover, under aprosthetic foot, or in a specially designed pump chamber attached to aspecific prosthetic foot. The second pump may be compressed due to thepositive pressure created on it during the heel strike stage of walking,causing the air and/or fluid to be transported through the conduit intothe chamber 425. This would advantageously allow a user to repeatedlypump any excess air out of the socket interior while walking forcontinuous suction suspension.

Another embodiment of the chamber is in FIG. 14, where the bladder 525is generally donut-shaped and secured between an inner plate 542 and mayinclude a stiff outer shift plate by a fastening member 546. Thefastening member 546 is further affixed to the socket by a flexiblemember 526, such as a rubber membrane, formed over a hole 514 in thesocket and defining a chamber therebetween.

The outer shift plate 544 is lifted away from the socket as thedonut-shaped bladder 525 expands due to the positive pressure introducedby a second pump preferably located under a prosthetic foot or within afoot cover. This causes the fastening member 546 to correspondinglyexpand the flexible member 526 and form an air chamber 550. Theresulting pressure differential draws air out of the socket interior andinto the air chamber 550. When the second pump is pumped with air and/orfluid into the chamber, the air chamber will return back to a zerovolume stage and correspondingly push the air and/or fluid back to thesecond pump adjacent the user's foot so it is ready for the nextcompression.

FIGS. 15 and 16 illustrate an embodiment of the vacuum suspension systemthat can secure a residual limb within a socket without a manuallycontrolled pump. Instead, the socket 610 includes a hole 614 forreceiving a fluid regulator 640, such as a one-way valve. A sealingcovering 622 is provided over the exterior surface of the socket 610 tocover the fluid regulator 640. A shift plate 644 is preferably securedbetween the covering 622 and the socket 610 at a location covering thefluid regulator 640.

It should be appreciated that the plate may be sealed to the socket viacompression applied by the covering, or it may be adhesively bonded tothe covering. Walking and other weight-bearing activities help createsuction suspension. As the residual limb is pushed further into thesocket, air is displaced out through the valve, and as the limb ispulled out of the socket during the swing phase of walking, suctionsuspension on the limb occurs since the valve will not permit air tore-enter the socket.

The resulting limb movement further into the socket 610 acts to pump airout of the socket interior through the fluid regulator 640. The air isaccumulated in a chamber defined by the space created between the plate644 and the socket 610. As a wearer walks, the relative movement of theresidual limb within the socket will repeatedly push excess air out fromwithin the socket through the fluid regulator 640 and into the chamber650. The air may then be expelled out into the environment as in theprevious embodiments. The covering 622 may include expulsion holes 628located adjacent to areas of the covering that form a sealing connectionwith the socket 610. These expulsion holes 628 allow the accumulated airwithin the chamber 650 to be released into the atmosphere.

The one-way valve 640 can also relieve a buildup of pressure when theliner-sheathed limb is first inserted into the socket 610. This preventsa positive air pressure inside the socket relative to the ambient airoutside to permit donning the socket while still providing a snug fitfor the limb. Easy donning is accomplished since air may beautomatically expelled as the limb is inserted into the socket. This isbecause the volume of the limb displaces the volume of air inside thesocket, forcing the remaining air out through the one-way valve. Any airexpelled through the one-way valve cannot re-enter the socket throughthe same channel. The suspension fit of the limb within the socket canbe preserved.

The invention claimed is:
 1. A vacuum suspension system, comprising: arigid socket defining a wall having exterior and interior surfaces, andan aperture extending between the exterior and interior surfaces, thesocket having a closed distal end and an open proximal end, the socketforming an interior cavity defined by the interior surface; a fluidregulator provided at the aperture; a pump system including a pump and acovering for securing over the exterior surface of the socket andsupporting the pump, the pump configured for placement proximate to thefluid regulator and arranged for drawing air from the socket through theaperture and operatively engaging the fluid regulator; a chamber havinga variable volume and formed by a space defined between the exteriorsurface of the socket and an inner surface of the covering; wherein thecovering defines a sleeve arranged to circumferentially secure about theexterior surface of the socket; wherein the covering defines a pluralityof expulsion holes defined at a location proximate the pump.
 2. Thevacuum suspension system of claim 1, wherein the pump system includes ahandle arranged for operating the fluid regulator and drawing air fromthe interior cavity of the socket.
 3. The vacuum suspension system ofclaim 2, wherein the covering is arranged to permit escape of air fromthe chamber upon release of the handle, and forms a one-way valve withthe exterior surface of the socket.
 4. The vacuum suspension system ofclaim 2, wherein the handle is generally elastic and returns to apredetermined first position both prior to and at release thereof, asthe handle is pulled away from the exterior surface of the socket. 5.The vacuum suspension system of claim 1, wherein the covering isarranged to seal against the exterior surface of the socket andselectively prevent escape of air from an interface formed between thecovering and the exterior surface.
 6. The vacuum suspension system ofclaim 5, wherein the covering seals against the exterior surface of thesocket at least in an area proximate to and extending over the aperture.7. The vacuum suspension system of claim 1, wherein the covering isdirectly attached to the exterior surface of the socket and forms thechamber with a variable volume.
 8. The vacuum suspension system of claim1, wherein the chamber is defined by a dome formed between the exteriorsurface of the socket and the inner surface of the covering.
 9. Thevacuum suspension system of claim 1, wherein the covering issubstantially more flexible than the exterior surface of the socket. 10.The vacuum suspension system of claim 1, wherein the covering iselastic.
 11. The vacuum suspension system of claim 1, wherein thecovering has at least one portion adapted to channel air from thechamber to the atmosphere.
 12. A vacuum suspension system, comprising: arigid socket defining a socket wall having exterior and interiorsurfaces, the socket defining an aperture extending between the exteriorand interior surfaces, the socket having a closed distal end and an openproximal end, the socket forming an interior cavity defined by theinterior surface; a fluid regulator provided at the aperture; a pumpcarried on a covering for securing over the exterior surface of thesocket, the pump configured for placement proximate to the fluidregulator and arranged for drawing air from the socket through theaperture and operatively engaging the fluid regulator; wherein the pumpsystem includes a handle arranged for operating the fluid regulator anddrawing air from the interior cavity of the socket; a chamber having avariable volume and formed by a space defined between the exteriorsurface of the socket and an inner surface of the covering proximate tothe pump, wherein the covering is arranged to permit escape of air fromthe chamber upon release of the handle, and forms a one-way valve withthe exterior surface of the socket; wherein the covering defines aplurality of expulsion holes defined at a location proximate the pump.13. The vacuum suspension system of claim 12, wherein the covering issubstantially more flexible than the exterior surface of the socket.